Differential reporting for beam groups or antenna panel groups

ABSTRACT

A method comprises: configuring multiple reporting modes for multi-level based transmitter (TX) beam index reporting for a particular beam/antenna panel group from a plurality of beam/antenna groups, wherein the multiple reporting modes includes at least one of a full reporting mode configuration for the particular beam/antenna panel group, a full reporting mode configuration common for the plurality of beam/antenna panel groups, a differential reporting mode, and a partial reporting mode, selecting a reporting mode from the multiple reporting modes, and sending a report based on the selected reporting mode.

TECHNICAL FIELD

The teachings in accordance with example embodiments of this inventionrelate generally to beam reporting modes and configurations.

BACKGROUND

This section is intended to provide a background or context to theinvention that is recited in the claims. The description herein mayinclude concepts that could be pursued, but are not necessarily onesthat have been previously conceived or pursued. Therefore, unlessotherwise indicated herein, what is described in this section is notprior art to the description and claims in this application and is notadmitted to be prior art by inclusion in this section.

The specification work of 5G New Radio (NR) in 3rd GenerationPartnership Project (3GPP) includes a work item in RAN1. The work itemhas a target to provide a full system specification, includingmulti-antenna functionality in above and below 6 GHz. The work itemaddresses operation in frequency bands above 6 GHz (which is currentlybeing introduced to 3GPP). A particular characteristic of thesefrequency bands is the fact that transmission of signals needs to happenbased on beamforming, due to the pathloss characteristics. The mainframework for such transmission is comprised by the beam managementwhich is defined as a set of Layer 1/Layer 2 (L1/L2) procedures toacquire and maintain a set of Tx/Rx Point(s) (TRP(s)) and/or UE beamsthat can be used for DL and UL transmission/reception, which include atleast following aspects: beam determination, measurement, reporting,sweeping.

Certain abbreviations that may be found in the description and/or in theFigures are herewith defined as follows:

-   -   AP Antenna Port    -   BI Beam Indices    -   CQI Channel Quality Indicator    -   CSI-RS Channel State Information Reference Signal    -   DCI Downlink Control Information    -   DL Downlink    -   DMRS Demodulation Reference Signal    -   FFS For further study    -   gNB, gNodeB Next generation base station    -   MAC CE Medium Access control element    -   NR-PDCCH New Radio Physical downlink Control Channel    -   PDSCH Physical Downlink Shared Channel    -   PUCCH Physical Resource Block    -   PUSCH Physical Uplink Shared Channel    -   RAN1 Radio Layer 1    -   RRC Radio resource control    -   RSRP reference signal received power    -   RX receiver    -   RS reference signals    -   TRP Tx/Rx Point    -   TX transmitter    -   UE User Equipment    -   UL Uplink

SUMMARY

The following summary is merely intended to be exemplary. The summary isnot intended to limit the scope of the claims.

In accordance with one aspect, an example method comprises: configuringmultiple reporting modes for multi-level based transmitter (TX) beamindex reporting for a particular beam/antenna panel group from aplurality of beam/antenna groups, wherein the multiple reporting modesincludes at least one of a full reporting mode configuration for theparticular beam/antenna panel group, a full reporting mode configurationcommon for the plurality of beam/antenna panel groups, a differentialreporting mode, and a partial reporting mode, selecting a reporting modefrom the multiple reporting modes, and sending a report based on theselected reporting mode.

In accordance with another aspect, an example apparatus comprises: atleast one processor; and at least one non-transitory memory includingcomputer program code, the at least one memory and the computer programcode configured to, with the at least one processor, cause the apparatusat least to perform: configure multiple reporting modes for multi-levelbased transmitter (TX) beam index reporting for a particularbeam/antenna panel group from a plurality of beam/antenna groups,wherein the multiple reporting modes includes at least one of a fullreporting mode configuration for the particular beam/antenna panelgroup, a full reporting mode configuration common for the plurality ofbeam/antenna panel groups, a differential reporting mode, and a partialreporting mode, select a reporting mode from the multiple reportingmodes, and send a report based on the selected reporting mode.

In accordance with another aspect, an example non-transitory computerprogram product comprising a computer-readable medium bearing computerprogram code embodied therein for use with a computer, the computerprogram code comprising code for configuring multiple reporting modesfor multi-level based transmitter (TX) beam index reporting for aparticular beam/antenna panel group from a plurality of beam/antennagroups, wherein the multiple reporting modes includes at least one of afull reporting mode configuration for the particular beam/antenna panelgroup, a full reporting mode configuration common for the plurality ofbeam/antenna panel groups, a differential reporting mode, and a partialreporting mode, selecting a reporting mode from the multiple reportingmodes; and sending a report based on the selected reporting mode.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other aspects of embodiments of this invention aremade more evident in the following Detailed Description, when read inconjunction with the attached Drawing Figures, wherein:

FIG. 1 is a block diagram of an example possible and non-limiting systemin which example embodiments may be practiced;

FIG. 2 shows an example of RX beam group and antenna panel group basedreporting configurations;

FIG. 3 shows an illustration of full group-wise multi-level based beamreport computation for the i-th beam group;

FIG. 4 shows an illustration of full non-group-wise multi-level basedbeam report computation for TX beam index reporting;

FIG. 5 shows an illustration of non-group-wise single-level differentialbased beam report for scheduled CSI-RS APs;

FIG. 6 shows an illustration of multi-level based differential beamreport for all groups;

FIG. 7 shows an illustration of multi-level beam report for N-previouslyreported TX beam indices allowing to track L<N new TX beam indices pergroup;

FIG. 8 shows an illustration of multi-level beam report for N-previouslyreported TX beam indices allowing to track L<N new strongest TX beamindices per group;

FIG. 9 shows an illustration of the utilization of different beamreporting modes; and

FIG. 10 shows a method in accordance with example embodiments which maybe performed by an apparatus.

DETAILED DESCRIPTION

In the example embodiments as described herein a novel method andapparatus is proposed to implement design of diverse multi-level beamreporting schemes comprising of beam reporting modes and configurations.A particular attribute of the proposal is that multi-level beamreporting schemes can reduce the feedback signalling overhead fordifferent beam/antenna panel group configurations.

Turning to FIG. 1 , this figure shows a block diagram of one possibleand non-limiting example system in which example embodiment may bepracticed. In FIG. 1 , a user equipment (UE) 110 is in wirelesscommunication with a wireless network 100. A UE is a wireless, typicallymobile device that can access a wireless network. The UE 110 includesone or more processors 120, one or more memories 125, and one or moretransceivers 130 interconnected through one or more buses 127. Each ofthe one or more transceivers 130 includes a receiver, Rx, 132 and atransmitter, Tx, 133. The one or more buses 127 may be address, data, orcontrol buses, and may include any interconnection mechanism, such as aseries of lines on a motherboard or integrated circuit, fiber optics orother optical communication equipment, and the like. The one or moretransceivers 130 are connected to one or more antennas 128. The one ormore memories 125 include computer program code 123. The UE 110 includesa control module 140, comprising one of or both parts 140-1 and/or140-2, which may be implemented in a number of ways. The control module140 may be implemented in hardware as control module 140-1, such asbeing implemented as part of the one or more processors 120. The controlmodule 140-1 may be implemented also as an integrated circuit or throughother hardware such as a programmable gate array. In another example,the control module 140 may be implemented as control module 140-2, whichis implemented as computer program code 123 and is executed by the oneor more processors 120. For instance, the one or more memories 125 andthe computer program code 123 may be configured to, with the one or moreprocessors 120, cause the user equipment 110 to perform one or more ofthe operations as described herein. The UE 110 communicates with eNB/gNB170 via a wireless link 111.

The base station 170 (for example, gNB for NR, new radio, oralternatively, an eNB for LTE long term evolution) provides access bywireless devices such as the UE 110 to the wireless network 100. The gNB170 includes one or more processors 152, one or more memories 155, oneor more network interfaces (N/W I/F(s)) 161, and one or moretransceivers 160 interconnected through one or more buses 157. Each ofthe one or more transceivers 160 includes a receiver, Rx, 162 and atransmitter, Tx, 163. The one or more transceivers 160 are connected toone or more antennas 158. The one or more memories 155 include computerprogram code 153. The gNB 170 includes a control module 150, comprisingone of or both parts 150-1 and/or 150-2, which may be implemented in anumber of ways. The control module 150 may be implemented in hardware ascontrol module 150-1, such as being implemented as part of the one ormore processors 152. The control module 150-1 may be implemented also asan integrated circuit or through other hardware such as a programmablegate array. In another example, the control module 150 may beimplemented as control module 150-2, which is implemented as computerprogram code 153 and is executed by the one or more processors 152. Forinstance, the one or more memories 155 and the computer program code 153are configured to, with the one or more processors 152, cause the gNB170 to perform one or more of the operations as described herein. Theone or more network interfaces 161 communicate over a network such asvia the links 176 and 131. Two or more gNBs 170 communicate using, forexample, link 176. The link 176 may be wired or wireless or both and mayimplement, for example, an X2 interface.

The one or more buses 157 may be address, data, or control buses, andmay include any interconnection mechanism, such as a series of lines ona motherboard or integrated circuit, fiber optics or other opticalcommunication equipment, wireless channels, and the like. For example,the one or more transceivers 160 may be implemented as a remote radiohead (RRH) 195, with the other elements of the gNB 170 being physicallyin a different location from the RRH, and the one or more buses 157could be implemented in part as fiber optic cable to connect the otherelements of the gNB 170 to the RRH 195.

The wireless network 100 may include a network control element (NCE) 190that may include MME (Mobility Management Entity)/SGW (Serving Gateway)functionality, and which provides connectivity with a further network,such as a telephone network and/or a data communications network (e.g.,the Internet). The gNB 170 is coupled via a link 131 to the NCE 190. Thelink 131 may be implemented as, e.g., an S1 interface. The NCE 190includes one or more processors 175, one or more memories 171, and oneor more network interfaces (N/W I/F(s)) 180, interconnected through oneor more buses 185. The one or more memories 171 include computer programcode 173. The one or more memories 171 and the computer program code 173are configured to, with the one or more processors 175, cause the NCE190 to perform one or more operations.

The wireless network 100 may implement network virtualization, which isthe process of combining hardware and software network resources andnetwork functionality into a single, software-based administrativeentity, a virtual network. Network virtualization involves platformvirtualization, often combined with resource virtualization. Networkvirtualization is categorized as either external, combining manynetworks, or parts of networks, into a virtual unit, or internal,providing network-like functionality to software containers on a singlesystem. Note that the virtualized entities that result from the networkvirtualization are still implemented, at some level, using hardware suchas processors 152 or 175 and memories 155 and 171, and also suchvirtualized entities create technical effects.

The computer readable memories 125, 155, and 171 may be of any typesuitable to the local technical environment and may be implemented usingany suitable data storage technology, such as semiconductor based memorydevices, flash memory, magnetic memory devices and systems, opticalmemory devices and systems, fixed memory and removable memory. Thecomputer readable memories 125, 155, and 171 may be means for performingstorage functions. The processors 120, 152, and 175 may be of any typesuitable to the local technical environment, and may include one or moreof general purpose computers, special purpose computers,microprocessors, digital signal processors (DSPs) and processors basedon a multi-core processor architecture, as non-limiting examples. Theprocessors 120, 152, and 175 may be means for performing functions, suchas controlling the UE 110, gNB 170, and other functions as describedherein.

In general, the various embodiments of the user equipment 110 caninclude, but are not limited to, cellular telephones such as smartphones, tablets, personal digital assistants (PDAs) having wirelesscommunication capabilities, portable computers having wirelesscommunication capabilities, image capture devices such as digitalcameras having wireless communication capabilities, gaming deviceshaving wireless communication capabilities, music storage and playbackappliances having wireless communication capabilities, Internetappliances permitting wireless Internet access and browsing, tabletswith wireless communication capabilities, as well as portable units orterminals that incorporate combinations of such functions.

Having thus introduced one suitable but non-limiting technical contextfor the practice of example embodiments of this invention, the exampleembodiments will now be described with greater specificity.

Beam grouping for TRP(s) or UE may be implemented as an operation togroup multiple Tx and/or Rx beam(s) and/or beam pair(s) into one subsetof beams. The basic and initial measurements on beams in are the form ofRSRP. In instances in which there are multiple (for example a multitudeof) beams to be measured, the systems and methods herein may implementreporting of RSRP.

In UE based beam grouping schemes, the UE 110 may form beam groups andfeedback this information to gNB 170. A beam group may be seen as acollection of downlink TX beams indices associated with a set of RXbeams, where the number of different RX beam groups is configurable by anetwork. In each beam group, there may be N-best downlink TX logicalbeam indices (BI)s according to a selected criterion. UE based beamgrouping schemes may allow the implementation of RX/TX beams in atransparent manner for a network based on the definition of the beamgroup. Furthermore, scheduling flexibility of gNB 170 may be enhanced byhaving more degrees of freedom in performing scheduling decisions andutilizing resources more effectively with respect to beam groupfeedback. Therefore, UE 110 based beam grouping may be implemented toenable flexible and efficient dynamic point switching and non-coherentmulti-point transmissions in New Radio (NR) systems. Moreover, based onthe enhanced scheduling flexibility with beam grouping, NR systems mayprovide significantly enhanced beam management robustness against, forexample, beam blockage, UE rotation and movement, etc.

To enable efficient use of beam grouping from the perspective of overallNR system design, it is highly important to guarantee that signallingoverheads related to beam grouping are minimized.

Referring now to FIG. 2 , an example 200 of RX Group and Panel basedoperations is shown.

FIG. 2 illustrates RX beam group 210 and an antenna panel group 250based reporting configurations. In this example 200, G1, G2, etc.,denotes different groups 230 (of beams) (shown as 230-g 1, 230-g 2,etc.) for RX beam group 210 and panel based grouping 250 reportingconfigurations. The major difference between these two alternatives (RXbeam group 210 and antenna panel group 250) is the number of beam groupsper UE RX antenna panel. For panel based grouping 250, the number ofbeam groups is limited to a single group (for example, one) whereas forRX beam grouping case the number of groups per panel may be larger thanone.

Beam reporting in NR is addressed by agreements issued in relation tothe 3GPP RAN1#88 meeting. Agreements regarding beam reporting in NR(see, RAN1-88-chairman-notes) include a confirmation of a workingassumption on group based beam reporting made in RAN1 Jan. NR Ad hocMeeting. The agreements include an update that indicates furtherdiscussion (for further study, FFS) for possible down-selection ormerging, (in particular, taking into account overhead).

NR supports the beam reporting considering L groups where L>=1 and eachgroup refers to an Rx beam set (alternative 1, Alt1) or a UE antennagroup (alternative 2, Alt2) depending on which alternative is adopted.For each group L, the UE 110 may report at least information indicatinga particular group, measurement quantities for N₁ beam(s), andinformation indicating N₁ DL Tx beam(s), when applicable.

UE 110 may report information indicating a particular group, at leastfor some cases (or instances). Condition(s) to omit this parameter, forexample, when L=1 or N₁=1, are designated as an area further study (FFS)from the 3GPP RAN1#88 meeting.

UE 110 may report measurement quantities for N₁ beam(s). Thesemeasurement quantities may support L1 RSRP and CSI report (when CSI-RSis for CSI acquisition). The details of RSRP/CSI derivation and contentare designated FFS. Other reporting contents, for example, RSRQ havealso been designated FFS. Configurability between L1 RSRP and CSIreport, and whether or not to support differential L1 RSRP feedback hasbeen designated FFS. Further, how to select N₁ beam(s), for example, maxN₁ beams in terms of received power being above a certain threshold orin terms of correlation less than a certain threshold, has beendesignated FFS.

UE 110 may report information indicating N₁ DL Tx beam(s) whenapplicable. The details on this information, for example, CSI-RSresource IDs, antenna port index, a combination of antenna port indexand a time index, sequence index, beam selection rules for assistingrank selection for MIMO tx, etc., have been designated FFS.

In some instances, group based beam reporting may be configurable per UE110 basis. The group based beam reporting may be turned off per UE 110basis, for example, when L=1 or N₁=1. No group identifier may bereported when the group identifier is turned off.

Areas that may be designated for further study include how L is to bedetermined, for example, by network configuration or UE selection or UEcapability (for example, how many beams can be received simultaneously).Additionally, configuration using the CSI framework to supportmulti-panel or multi-TRP transmission is also designated FFS.

Example embodiments of the systems included herein provide exampledesigns for diverse multi-level beam reporting schemes comprising ofbeam reporting modes and configurations. Particularly, exampleembodiments of multi-level beam reporting schemes disclosed herein mayreduce the feedback signalling overhead for different beam/antenna panelgroup configurations.

In one example embodiment, multi-level based TX beam index reporting isdefined for a beam group and/or antenna panel group. TX beam index mayalso be defined as configured RS resource, RS resource index, or RSantenna port where RS may be CSI-RS, DMRS of NR-PDCCH, NR_PDSCH or anyRS enabling beam management functionality. The multi-level beamreporting may be configured to operate in full or differential orpartial reporting mode. Differential and partial beam reports may havedependency to previous beam report, while a full report may beindependent of previous report. The multi-level beam report may consistof one or more elements for each beam group/antenna panel. Multi-levelbased TX beam index reporting may include a full reporting modeconfigurations for a particular beam/antenna panel group, a fullreporting mode configurations common for all beam/antenna panel groups,differential reporting modes, and partial reporting modes, etc.

According to an example, a full reporting mode configuration for aparticular beam/antenna panel group may include a beam/antenna panelgroup ID for the i-th group. The full reporting mode configuration forthe particular beam/antenna panel group may include maximum RSRP valueof the i-th group in dB (or, alternatively, may use RSRP index frompredefined table 'RSRP index to measurement quantity mapping, forexample, 7 bit range for −140 dBm to −40 dBm. Alternatively, othermeasurement quantities may not be excluded, such as channel qualityindicator (CQI), RSRQ, etc.

The full reporting mode configuration for a particular beam/antennapanel group may include relative power resolution window for the i-thgroup, Δ_(i) in dB, which may be defined as(max({RSRP}_(i))−min({RSRP}))/(K_(i)−1), where operator { }_(i) definesa set of values for the i-th group, and where K_(i) is the number ofpower levels determined as K_(i)=2^(n) and n-bit offset value. The valueof K_(i) may be configured group-specifically by a network.Alternatively, a network may also signal/pre-configure a relative powerresolution window user-specifically. The reported RSRP values may bebased on averaging of different measurement instants within a networkconfigured measurement window. The full reporting mode configuration forthe particular beam/antenna panel group may include relative n-bitrelative power offset value defining differential power offset withrespect to the maximum RSRP value of the i-th group. The full reportingmode configuration for the particular beam/antenna panel group may alsoinclude N-different TX beam indices for the i-th group.

According to an example, a full reporting mode configuration common forall beam/antenna panel groups. This may provide a common report for allbeam/antenna panel groups. The full reporting mode configuration commonfor all beam/antenna panel groups may include a maximum RSRP value in dBassociated over all configured beam/antenna panel groups.

The full reporting mode configuration common for all beam/antenna panelgroups may further include the list of simultaneously usable beam groupsor capability to simultaneously use reported beam groups, for example,0=no 1=yes (depending on configuration defined by a network), and arelative power resolution window common for all groups, A in dB, whichmay be defined as Δ=(max ({RSRP_(j)})−min ({RSRP_(j)}₁))/(K−1), where{RSRP_(j)}_(i) is the j-th of element of the i-th set and the index j=1,. . . , N and i=1, . . . I, where N defines the number RSPR values in aset and I being the number of sets. Alternatively, a network may alsosignal/pre-configure relative power resolution window user-specificallyfor all groups.

The operators max and min operators may select the maximum and minimumvalues over all different sets. The parameter K may define a number ofpower levels determined as K=2^(n) and n-bit offset value. The value ofK may be configured by devices in a network 100. The reported RSRPvalues may be based on averaging of different measurement instantswithin network configured measurement window.

The full reporting mode configuration common for all beam/antenna panelgroups may further include group-specific reporting. Group-specificreporting may include a beam/antenna panel group ID. Group-specificreporting may also include a relative n-bit relative power offset valuedefining differential power offset to the maximum RSRP value over allbeam/antenna panel groups. Group-specific reporting may further includeN-different TX beam indices for the i-th group.

According to an example, differential reporting modes may include asingle-level non-group-wise differential beam report. The single-levelnon-group-wise differential beam report may be common for all beamgroups and include a maximum RSRP value over beam groups (which may bemeasured in [dB]). For each beam group, the single-level non-group-wisedifferential beam report may include N different 1-bit relative poweroffset value for each antenna panel (AP) to indicate whether RSRP valueis greater or equal to a configured power resolution window. In thisinstance, a network 100 may perform (or have performed) the mapping ofTX beam indices to N positions.

The differential reporting modes may include multi-level non-group-wisedifferential beam report for N scheduled CSI-RS APs or N-previouslyreported TX beams. The multi-level non-group-wise differential beamreport may be common for all beam groups and may include a maximum RSRPvalue over beam groups [dB] the list of simultaneously usable beamgroups or capability to simultaneously use reported beam groups, forexample 0=no 1=yes (depending on configuration defined by a network).The maximum RSRP value may only be reported if the measured maximum RSRPvalue differs Y dB from the previously reported maximum RSRP value. Theset of maximum RSRP power difference values may be configureduser-specifically via RRC signalling and indicated dynamically viadownlink grant/uplink grant via DCI.

For each beam group, the multi-level non-group-wise differential beamreport may include N TX beams n-bit relative power offset from themaximum RSRP value over beam groups. The network may configure themapping of TX beam indices to N positions per beam group. Additionally,in some instances, source coding may be applied to further compress thesignalled bits, for example, run-length, Lempel-Ziv, etc.

According to an example, partial reporting modes may include amulti-level partial beam report for N-previously reported TX beamindices enabling TX beam tracking capability of L<N new TX beams. Themulti-level partial beam report for N-previously reported TX beamindices may be common for all beam groups and may include a maximum RSRPvalue over beam groups [dB]. The maximum RSRP value may only reported ifthe measured maximum RSRP value differs Y dB from the previouslyreported maximum RSRP value. Value Y may be different depending onwhether the measured maximum RSRP value is higher or lower than thepreviously reported maximum, for example, if measured max RSRP is higherthe Y may have higher value and if lower the Y value may be lower. Theset of maximum RSRP power difference values may be configureduser-specifically via RRC signalling and indicated dynamically viadownlink grant/uplink grant via DCI.

Common to all beam groups for multi-level partial beam report forN-previously reported TX beam indices with tracking TX beam trackingcapability of L<N new TX beams, the relative power resolution value mayonly be reported if the computed power resolution value differs X dBfrom previously reported relative power resolution value. The set ofpower resolution window difference values may be configureduser-specifically via RRC signalling and indicated dynamically viadownlink grant/uplink grant via DCI.

Multi-level partial beam report for N-previously reported TX beamindices may enable the TX beam tracking capability of L<N new TX beams.The partial beam report may include, for each beam group, informationfor N TX beams n-bit relative power offset from the maximum RSRP valueover beam groups (network 100 may perform the mapping of TX beam indicesto N positions). In some instances, source coding may be applied tofurther compress the signalled bits, for example, run-length,Lempel-Ziv, etc. Multi-level partial beam report for N-previouslyreported TX beam indices with tracking TX beam tracking capability ofL<N new TX beams may include, for each beam group, L m-bit new TX beampositions (2^(m) bit combination available where code word with m zerosis reserved to indicate no new beam in a group). In some instances,source coding may be applied to further compress the signalled bits, forexample, run-length, Lempel-Ziv, etc. Additionally, the multi-levelpartial beam report may include L new TX beam indices not being part ofprevious beam report, where L<N.

Multi-level partial beam report for N-previously reported TX beamindices with TX beam tracking capability of L<N new strongest TX beamsmay include common information for all beam groups. This may include amaximum RSRP value over beam groups [dB]. The maximum RSRP value mayonly be reported if the measured maximum RSRP value differs Y dB fromthe previously reported maximum RSRP value. The set of maximum RSRPpower difference values may be configured user-specifically via RRCsignalling and indicated dynamically via downlink grant/uplink grant viaDCI. The relative power resolution value may only be reported if thecomputed power resolution value differs X dB from previously reportedrelative power resolution value. The set of power resolution windowdifference values may be configured user-specifically via RRC signallingand indicated dynamically via downlink grant/uplink grant via DCI.

Multi-level partial beam report for N-previously reported TX beamindices with TX beam tracking capability of L<N new strongest TX beamsmay include information for each beam group. The information may includeL new strongest TX beams in terms of RSRP not being part of previousbeam report, where L<N.

According to an example embodiment, single-level based antenna portreporting is defined for a beam group and/or antenna panel group. Thisreporting may include a maximum RSRP value over beam groups [dB]. Foreach beam group, the single-level based antenna port reporting mayinclude a 1-bit value for each AP to indicate whether RSRP value isgreater or equal to configured relative power offset from the maximum.Alternatively, for each beam group, single-level based antenna portreporting may include a single bit indication if RSRP value is abovepreconfigured/signalled absolute threshold. Single-level based antennaport reporting may include AP indices.

According to an example embodiment, a network 100 (or device in network100) may configure beam/antenna panel beam reporting to be as acombination of full, differential and partial beam reports.

In an example embodiment, a network 100 may pre-configure differentialRSRP beam reporting for two different reporting modes, for example,reference signal, such as CSI-RS, antenna port and TX beam index basedoperations. The pre-configuration may be done user-specifically via RRCsignalling a beam group-wise or using same configuration for all beamgroups.

The pre-configuration may encapsulate one or more of the followingparameters:

-   -   Set of different power resolution levels, for example, {K₁, K₂,        . . . K_(p),} where K_(P) defines the P-th number of power        resolution levels; and    -   Set of relative power resolution window values, where each value        defines the power difference from the maximum RSRP value.

In an example embodiment, a PUCCH (also for PUSCH and MAC CE) based beamreport may be defined as a bit map, which may be used to represent thepreviously reported APs/beam indices or the configured APs for beammeasurements. In bit map based reporting specific beam IDs/APs areassociated to specific bit positions in the map. For example, UE 110 mayreport N=4 beams thus the bitmap may have length 4 bits, each bitposition corresponding to a beam ID/AP. This may be a partial ordifferential beam report based on the full report. In a differentialbeam report, only relative power offset RSRP values may be reported. Ina partial report, not existing TX beam indices may be reportedassociated with relative power offset values. In bit map based reportingUE may have previously reported MAX RSRP and beam/AP indices and maythen be configured to report by single bit (‘1’ above/equal or ‘0’below) indication whether a beam RSRP value is above the configuredrelative threshold value (relative to reported MAX RSRP). Alternativelya bit map may be used to report all beams/APs above an absolutethreshold. UE 110 may update the corresponding beam IDs/APs in thebitmap by sending a full report. Alternatively, network may configure UE110 to measure set of APs that UE 110 refers with a bit map. Signallingmay be applied to a beam group or multiple beam groups or over all beamgroups.

In an example embodiment, a PUSCH/MAC based beam report may be definedas a full report or alternatively, a partial report. The partial reportmay refer to the full AP index/beam index by bitmap/listing order of thebeam/port IDs.

Referring now to FIG. 3 , an example of full group-wise multi-levelbased beam report computation for TX beam index reporting is shown.

FIG. 3 illustrates an example of full group-wise multi-level based beamreport computation for the i-th beam group in which values for RSRP 310,TX beam index 320 and Offset bits 330 are presented in graphical formincluding offset bits for ith groups 360.

In this instance, a network 100 may have configured UE 110 to performRSRP measurements and reporting for N-best TX beam indices per beamgroup associated with RSRP values. For full group-wise reporting commonfor all beam/antenna panel groups include the list of simultaneouslyusable beam groups or capability to simultaneously use reported beamgroups, for example, 0=no 1=yes (depending on configuration defined by anetwork 100). For the full group-wise multi-level based beam reportcomputation, both maximum 340 and minimum 350 RSRP values of a beamgroup i with the number of power resolution levels K=2^(n) may be usedto compute uniform power resolution window for a reported differentialRSRP values, where n is the number of bits for power levels. Morespecifically, K−1 different power resolution windows may be computedbetween maximum and minimum RSRP values where each power resolutionwindow may be calculated as: Δ_(i)=(max_(j)({RSRP}_(i))−min_(j)({RSRP}_(i)))/(K−1), where operator { } defines a set of values. The setof different relative power resolution levels may be pre-configured userspecifically via RRC signalling and an intended specific value of K canbe dynamically indicated via downlink or uplink grant via DCI.Alternatively, a network 100 may also preconfigure absolute powerresolution levels without imposing UE 100 to compute them the absolutepower resolution levels dynamically. Each of RSRP values may be roundedto the closest power level and corresponding quantized RSRP relativepower offset bit-level information may be generated. Accordingly, as aresult of the rounding of the power level and generation of thecorresponding quantized RSRP relative power offset bit-level, onlyoffset values from the maximum power level may be reported for each TXbeam index. The beam report may be transmitted via physicaluser-specific uplink control channel, for example, PUCCH, or as a partof PUSCH/MAC CE.

The required feedback may be summarised in a first alternative (Alt #1)as: Group-wise beam/antenna panel group report for TX beam. Beamreporting may consist of common for all beam/antenna panel groups thelist of simultaneously usable beam groups or capability tosimultaneously use reported beam groups, for example, 0=no 1=yes(depending on configuration defined by a network 100), and particularvalues for each group, such as a Beam group ID, a maximum RSRP [dB], anda relative power resolution window, Δ_(i), [dB]. Beam reporting may alsoconsist of n-bit power offset. Additionally, source coding may beapplied to further compress the signalled bits, for example, run-length,Lempel-Ziv, etc. Beam reporting may also consist of TX beam indicesrepresented with Q-bits.

By using reported beam group feedback, beam group-specific quantizedRSRP values can be reconstructed at gNB 170 as follows. The maximum RSRPvalue may be used as a reference value for the computation of rest ofRSRP values. For each reported TX beam index, a corresponding quantizedRSRP value may be obtained by subtracting the product of offset bits (in10-base system) and power resolution window from the maximum RSRP value.

Referring to FIG. 4 an example 400 of full non-group-wise multi-levelbased beam report computation for TX beam index reporting is shown. Inparticular, an example of full non-group-wise multi-level based beamreport for two beam groups, beam group 1 (450) (with values denoted by asolid line) and beam group 2 (460) (with values denoted by a dashedline) showing an RSRP 310 in relation to a position 410 for the beamgroups.

In comparison of to the Alt-1 scheme discussed above with respect toFIG. 3 , the maximum RSRP 340 and minimum RSRP 350 values over all beamgroups may be used for a computation power resolution window. As aresult of this, the feedback of a power resolution window may be omittedfor each group as well as enabling the reported RSRP values overdifferent beam groups to be comparable in terms of power andgranularity. The required parameters of beam reporting may be assummarized as discussed with respect to alternative 2 (Alt #2).

Alt #2 may include non-group-wise beam/antenna panel group report for TXbeam indices. Beam reporting, common for all groups, may consist of thelist of simultaneously usable beam groups or capability tosimultaneously use reported beam groups, for example, 0=no 1=yes(depending on configuration defined by a network 100), maximum RSRPvalue over beam groups [dB] and relative power resolution window, Δ(470), fixed over different beam groups [dB]. For each beam/antennapanel group, beam reporting may consist of a beam group ID. Beamreporting may also consist of N TX beams n-bit relative power offsetfrom the maximum RSRP value over beam groups. Some source coding may beapplied to further compress the signalled bits, for example, run-length,Lempel-Ziv, etc. Beam reporting may also consist of N-TX beam indicesrepresented with Q-bits.

To reduce signalling overheads related to the CSI-RS antenna port (AP)as well as TX beam index based reporting modes, the network 100 maydefine different differential reporting modes. In basic differentialreporting mode, scheduled CSI-RS APs or previously reported TX beamindices may be tracked by identifying whether these elements are withina certain power window from the maximum RSRP value or not.

Referring to FIG. 5 an example 500 of non-group-wise single-leveldifferential based beam report for scheduled CSI-RS APs is shown. Anexample of single-level based differential report for two beam groups,beam group 1 (450) (with values denoted by a solid line) and beam group2 (460) (with values denoted by a dashed line), with AP or TX beam indexbased reporting is illustrated.

In instances of TX beam index reporting, AP indices may be replaced bythe positions 410 (shown as 1 to 6) of previously reported TX beamindices. Additionally, assumed device in network 100 may assume that TXbeam indices are the same with respect to previously reported TX beamindices. According to an example of TX beam index reporting, the devicemay assume that position 1 is mapped at network side to TX beam index xand position 2 to TX beam index y, etc. The network 100 may configurevia RRC signalling to UE 110 a set of different relative powerresolution window values from which the desired value is dynamicallyselected via downlink grant/uplink with DCI. The maximum RSRP value overbeam groups may be selected as a reference value from a single-levelpower threshold is formed by subtracting from the maximum RSRP value theselected power resolution window value. By using single-level powerthreshold, relative power offset bit values may be computed by comparingRSRP value to the threshold. If the measured RSRP value is larger orequal to the threshold value, a group-specific offset bit may be definedas one. Otherwise, the group-specific offset bit is equal to zero.

Alternative 3 (Alt #3) includes a single-level non-group-wisedifferential beam report for N scheduled CSI-RS APs or N-previouslyreported TX beams. The single-level differential beam reporting, commonfor all beam groups, may consist of a maximum RSRP value over beamgroups [dB]. The single-level differential beam reporting, for each beamgroup, may consist of N different 1-bit relative power offset value foreach AP to indicate whether RSRP value is greater or equal to aconfigured power resolution window. Network 100 may have performed themapping of TX beam indices to N positions.

Referring to FIG. 6 an example 600 of multi-level based differentialbeam report for all groups is shown. FIG. 6 illustratesmulti-level-level based differential beam report that may be transmittedby a UE 110 for a beam or antenna panel group.

Similar to Alt #3 discussed above with respect to FIG. 5 , the devicesin the network 100 may assume that the instance of TX beam indexreporting AP indices may be replaced by the positions of previouslyreported TX beam indices. Additionally, the devices in the network 100may assume that TX beam indices are the same with respect to previouslyreported TX beam indices. With regard to instances of TX beam indexreporting, the devices in the network 100 may assume that the position 1is mapped at network side to TX beam index x and the position 2 to TXbeam index y, etc. Furthermore, the devices in the network 100 mayassume that the relative power resolution window value may also beconfigured by a network 100 based on previous beam reports. In thisinstance, relative power resolution window values are not required (orneeded) to be reported. In comparison to Alt #3, the multi-level mayenable the network devices to track RSRP value changes over configuredreporting elements.

Alternative 4 (Alt #4) may include multi-level non-group-wisedifferential beam report for N scheduled CSI-RS APs or with respect toN-previously reported TX beam indices. Multi-level differential beamreporting, common for all beam groups, may consist of the list ofsimultaneously usable beam groups or capability to simultaneously usereported beam groups, for example, 0=no 1=yes (depending onconfiguration defined by a network 100) and maximum RSRP value over beamgroups [dB].

Multi-level differential beam reporting, for each beam group, mayconsist of N TX beams n-bit relative power offset from the maximum RSRPvalue over beam groups. Network 100 may have performed the mapping of TXbeam indices to N positions. Some source coding may be applied tofurther compress the signalled bits related to TX beam indices and poweroffset values, for example, run-length, Lempel-Ziv, etc.

Referring to FIG. 7 an example 700 of multi-level beam report forN-previously reported TX beam indices allowing to track L<N new TX beamindices per group is shown. FIG. 7 illustrates an example of multi-levelbased partial beam report with capability to track L new TX beams (shownas L=2, 710 and 720) for each two beam groups.

This beam reporting format may be targeted to enable the tracking ofL-new strongest TX beams that were not as part of previously reported TXbeams.

Alternative 5 (Alt #5) may provide a multi-level partial beam report forN-previously reported TX beam indices with tracking TX beam trackingcapability of L<N new TX beams. Multi-level partial beam reporting,common for all beam groups, may consist of maximum RSRP value over beamgroups [dB].

Multi-level partial beam reporting, for each beam group, may consist ofN TX beams n-bit relative power offset from the maximum RSRP value overbeam groups (network 100 may have performed the mapping 730 of TX beamindices to N positions). Some source coding may be applied to furthercompress the signalled bits, for example, run-length, Lempel-Ziv, etc.Multi-level partial beam reporting, for each beam group, may furtherconsist of L m-bit new TX beam positions 740, 750 (for example, 2^(m)bit combination available where code-word with m zeros is reserved toindicate no new beam in a group). Some source coding may be applied tofurther compress the signalled bits, for example, run-length,Lempel-Ziv, etc. Multi-level differential beam reporting, for each beamgroup, may also consist of L new TX beam indices not being part ofprevious beam report, where L<N.

Referring to FIG. 8 , an example of multi-level beam report forN-previously reported TX beam indices allowing to track L<N newstrongest TX beam indices per group is shown. Network 100 may usemulti-level based partial beam report with a capability to track L newstrongest TX beams for each of the multiple (for example, two) beamgroups. For example, for two groups, 2 L strongest beams may be tracked.

The beam reporting format may be targeted to enable the tracking ofL-new strongest TX beams that were not included as part of previouslyreported TX beams. With regard to Alt #6 (which is further discussedherein below), multi-level beam report may not be required to containposition information because only L new strongest TX beams may bereported resulting in further reduced signalling overhead. gNB 170 mayassociate reported new TX beams to reported beam positions based on userof reported relative power offset value information.

Alternative 6 (Alt #6) provides a multi-level partial beam report forN-previously reported TX beam indices with tracking TX beam trackingcapability of L<N new strongest TX beams. Multi-level partial beamreporting, common for all beam groups, may consist of a maximum RSRPvalue(s) over beam groups [dB]. Multi-level partial beam reporting, foreach beam group, may consist of N TX beams n-bit relative power offsetfrom the maximum RSRP value over beam groups (network 100 may haveperformed the mapping 730 of TX beam indices to N positions). Somesource coding may be applied to further compress the signalled bits, forexample, run-length, Lempel-Ziv, etc. Multi-level differential beamreporting, for each beam group, may further consist of L new strongestTX beams in terms of RSRP not being part of previous beam report, whereL<N.

Referring to FIG. 9 , an illustration 900 of the utilization ofdifferent beam reporting modes is shown.

Different reporting modes and required resources may be pre-configureduser-specifically via RRC signalling. For example, a full report 910(shown, by way of illustration, as 940-a and 940-b) and adifferential/partial report 950 (shown, by way of illustration, as 950-xand 950-y) may be pre-configured for the UE 110. Then, the usedreporting mode and corresponding resources may be indicated dynamicallyfor a UE 110 via downlink/uplink grant via DCI. For example, as shownalong a time axis 910, at time 920-a, a full report 910-a may beindicated. The full report 920 may be a complete full report with nodependency to previous reports (for example, as shown at report 940-b,indicated at time 920-b). At a time 930-x, a differential/partial report950-x may be indicated. The differential/partial report 950 may use asame power resolution window setting as with full report over differentdifferential reports. The differential/partial report 950 may reportonly TX beam indices if their RSRP values have changed from theirprevious level to another level or if new TX beam index arrives to theset of N best beams. The differential/partial report 950 may enable lowsignalling overhead TX beam tracking.

Each of the reports may be configured to be periodic/semi-persistent oraperiodic. The beam reporting may be done by either using MAC CE or viaphysical uplink control channel. The network 100 may mainly use MAC CEfor the full scale beams reports based on the ability to carry largerpayload size with MAC CE signalling. The network 100 may then updatefull scale beam reports 940 with differential or partial beam reports950. Network 100 may leverage a combination of differential and partialreporting modes to significantly reduce feedback signalling overheadwith respect to full beam reporting mode.

Referring to FIG. 10 an example method 1000 for multi-level baseddifferential beam reporting is shown.

At block 1010, the method may include configuring (or providingconfiguration information to UE 110 for) multi-level based TX beam indexreporting for a beam group 210 and/or antenna panel group 250 (such asdescribed above with respect to FIG. 2 ). The multi-level beam reportingmay be configured to operate in full or differential reporting mode. Themulti-level beam report may consist of one or more elements for eachbeam group/antenna panel, such as described above with respect to FIGS.2 to 8 .

At block 1020, the method may include selecting a reporting modeconfiguration from multiple reporting modes for the multi-level baseddifferential beam reporting. For example, the UE 110 may select areporting mode from a full reporting mode configuration for abeam/antenna panel group 210/250 specifically, a full reporting modeconfiguration common for all beam/antenna panel groups, a differentialreporting mode, or a partial reporting mode.

At block 1030, the method may include the UE 110 receiving an indicationand transmitting a report to gnB 170 based on a configured modedetermined (or a reporting mode selected) from block 1020.

Without in any way limiting the scope, interpretation, or application ofthe claims appearing below, a technical effect of one or more of theexample embodiments disclosed herein may facilitate reduced signalingoverhead related to beam/antenna panel group reporting. Anothertechnical effect of one or more of the example embodiments disclosedherein enables a network to flexibly configure different user-specificbeam reports according to network needs and scenario, for example, acombination of full and differential reports. Another technical effectof one or more of the example embodiments disclosed herein enablespotentially low latency reporting as smaller amount of resources may beneeded to report.

An example embodiment may provide a method that comprises configuringmultiple reporting modes for multi- and/or single-level basedtransmitter (TX) beam index reporting for a particular beam/antennapanel group from a plurality of beam/antenna groups, wherein themultiple reporting modes includes at least one of a full reporting modeconfiguration for the particular beam/antenna panel group, a fullreporting mode configuration common for the plurality of beam/antennapanel groups, a differential reporting mode, and a partial reportingmode, selecting a reporting mode from the multiple reporting modes, andsending a report based on the selected reporting mode.

An example embodiment may be provided in an apparatus comprising atleast one processor; and at least one non-transitory memory includingcomputer program code, the at least one memory and the computer programcode may be configured to, with the at least one processor, cause theapparatus to: configure multiple reporting modes for multi-level basedtransmitter (TX) beam index reporting for a particular beam/antennapanel group from a plurality of beam/antenna groups, wherein themultiple reporting modes includes at least one of a full reporting modeconfiguration for the particular beam/antenna panel group, a fullreporting mode configuration common for the plurality of beam/antennapanel groups, a differential reporting mode, and a partial reportingmode, select a reporting mode from the multiple reporting modes, andsend a report based on the selected reporting mode.

An example embodiment may be provided non-transitory computer programproduct comprising a computer-readable medium bearing computer programcode embodied therein for use with a computer, the computer program codecomprising code for configuring multiple reporting modes for multi-levelbased transmitter (TX) beam index reporting for a particularbeam/antenna panel group from a plurality of beam/antenna groups,wherein the multiple reporting modes includes at least one of a fullreporting mode configuration for the particular beam/antenna panelgroup, a full reporting mode configuration common for the plurality ofbeam/antenna panel groups, a differential reporting mode, and a partialreporting mode, selecting a reporting mode from the multiple reportingmodes, and sending a report based on the selected reporting mode.

In accordance with another example, an example apparatus comprises:means for configuring multiple reporting modes for multi-level basedtransmitter (TX) beam index reporting for a particular beam/antennapanel group from a plurality of beam/antenna groups, wherein themultiple reporting modes includes at least one of a full reporting modeconfiguration for the particular beam/antenna panel group, a fullreporting mode configuration common for the plurality of beam/antennapanel groups, a differential reporting mode, and a partial reportingmode, means for selecting a reporting mode from the multiple reportingmodes, and means for sending a report based on the selected reportingmode.

Embodiments herein may be implemented in software (executed by one ormore processors), hardware (e.g., an application specific integratedcircuit), or a combination of software and hardware. In an exampleembodiment, the software (e.g., application logic, an instruction set)is maintained on any one of various conventional computer-readablemedia. In the context of this document, a “computer-readable medium” maybe any media or means that can contain, store, communicate, propagate ortransport the instructions for use by or in connection with aninstruction execution system, apparatus, or device, such as a computer,with one example of a computer described and depicted, e.g., in FIG. 1 .A computer-readable medium may comprise a computer-readable storagemedium (e.g., memories 125, 155, 171 or other device) that may be anymedia or means that can contain, store, and/or transport theinstructions for use by or in connection with an instruction executionsystem, apparatus, or device, such as a computer. A computer-readablestorage medium does not comprise propagating signals.

If desired, the different functions discussed herein may be performed ina different order and/or concurrently with each other. Furthermore, ifdesired, one or more of the above-described functions may be optional ormay be combined.

Although various aspects are set out above, other aspects comprise othercombinations of features from the described embodiments, and not solelythe combinations described above.

It is also noted herein that while the above describes exampleembodiments, these descriptions should not be viewed in a limitingsense. Rather, there are several variations and modifications which maybe made without departing from the scope of the present invention.

Although various aspects of the invention are set out in the independentclaims, other aspects of the invention comprise other combinations offeatures from the described embodiments and/or the dependent claims withthe features of the independent claims, and not solely the combinationsexplicitly set out in the claims.

It is also noted herein that while the above describes exampleembodiments, these descriptions should not be viewed in a limitingsense. Rather, there are several variations and modifications which maybe made without departing from the scope of the present invention asdefined in the appended claims.

In general, the various embodiments may be implemented in hardware orspecial purpose circuits, software, logic or any combination thereof.For example, some aspects may be implemented in hardware, while otheraspects may be implemented in firmware or software which may be executedby a controller, microprocessor or other computing device, although theinvention is not limited thereto. While various aspects of the inventionmay be illustrated and described as block diagrams, flow charts, orusing some other pictorial representation, it is well understood thatthese blocks, apparatus, systems, techniques or methods described hereinmay be implemented in, as non-limiting examples, hardware, software,firmware, special purpose circuits or logic, general purpose hardware orcontroller or other computing devices, or some combination thereof.

Embodiments may be practiced in various components such as integratedcircuit modules. The design of integrated circuits is by and large ahighly automated process. Complex and powerful software tools areavailable for converting a logic level design into a semiconductorcircuit design ready to be etched and formed on a semiconductorsubstrate.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any embodiment described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other embodiments. All of the embodiments described inthis Detailed Description are example embodiments provided to enablepersons skilled in the art to make or use the invention and not to limitthe scope of the invention which is defined by the claims.

The foregoing description has provided by way of non-limiting examples afull and informative description of the best method and apparatuspresently contemplated by the inventors for carrying out the invention.However, various modifications and adaptations may become apparent tothose skilled in the relevant arts in view of the foregoing description,when read in conjunction with the accompanying drawings and the appendedclaims. However, all such and similar modifications of the teachings ofthis invention will still fall within the scope of this invention.

It should be noted that the terms “connected,” “coupled,” or any variantthereof, mean any connection or coupling, either direct or indirect,between two or more elements, and may encompass the presence of one ormore intermediate elements between two elements that are “connected” or“coupled” together. The coupling or connection between the elements canbe physical, logical, or a combination thereof. As employed herein twoelements may be considered to be “connected” or “coupled” together bythe use of one or more wires, cables and/or printed electricalconnections, as well as by the use of electromagnetic energy, such aselectromagnetic energy having wavelengths in the radio frequency region,the microwave region and the optical (both visible and invisible)region, as several non-limiting and non-exhaustive examples.

Furthermore, some of the features of the preferred embodiments of thisinvention could be used to advantage without the corresponding use ofother features. As such, the foregoing description should be consideredas merely illustrative of the principles of the invention, and not inlimitation thereof.

The invention claimed is:
 1. A method, comprising: configuring, by auser equipment, at least one reporting mode for transmitter beam indexreporting for a particular beam/antenna panel group from a plurality ofbeam/antenna groups, wherein the at least one reporting mode comprisesat least one of a full reporting mode configuration for the particularbeam/antenna panel group, a full reporting mode configuration common forthe plurality of beam/antenna panel groups, a differential reportingmode, and a partial reporting mode; and sending a report based on theconfigured at least one reporting mode.
 2. The method of claim 1,wherein the full reporting mode configuration for the particularbeam/antenna panel group comprises at least one of: a beam/antenna panelgroup identification for the particular beam/antenna panel group, amaximum reference signal received power (RSRP) value of the particularbeam/antenna panel group, a relative power resolution window for theparticular beam/antenna panel group in decibel (dB), a pre-configuredrelative power resolution window in dB, a relative n-bit relative poweroffset value defining differential power offset with respect to themaximum RSRP value of the particular beam/antenna panel group, andN-different transmitter beam indices for the particular beam/antennapanel group.
 3. The method of claim 1, wherein the full reporting modeconfiguration common for the plurality of beam/antenna panel groupsincludes at least one of: a common report for the plurality ofbeam/antenna panel groups; and group-specific reporting.
 4. The methodof claim 3, wherein the common report for the plurality of beam/antennapanel groups comprises at least one of: a maximum reference signalreceived power value associated with the plurality of beam/antenna panelgroups, one of a relative power resolution window common for theplurality of beam/antenna panel groups, and a pre-configured relativepower resolution window in dB.
 5. The method of claim 3, wherein thegroup-specific reporting comprises at least one of: a beam/antenna panelgroup identification, a relative n-bit relative power offset valuedefining differential power offset to a maximum reference signalreceived power value over the plurality of beam/antenna panel groups,and N-different transmitter beam indices for a beam/antenna panel group.6. The method of claim 1, wherein the differential reporting modeincludes at least one of a single-level non-group-wise differential beamreport and a multi-level non-group-wise differential beam report for Nscheduled Channel State Information Reference Signal (CSI-RS) antennaports (APs) or N-previously reported transmitted beams per group.
 7. Anapparatus, comprising: at least one processor; and at least onenon-transitory memory including computer program code, the at least onememory and the computer program code configured to, with the at leastone processor, cause the apparatus to at least: configure at least onereporting mode for transmitter beam index reporting for a particularbeam/antenna panel group from a plurality of beam/antenna groups,wherein the at least one reporting mode comprises at least one of a fullreporting mode configuration for the particular beam/antenna panelgroup, a full reporting mode configuration common for the plurality ofbeam/antenna panel groups, a differential reporting mode, and a partialreporting mode; and send a report based on the configured at least onereporting mode.
 8. The apparatus of claim 7, wherein the full reportingmode configuration for the particular beam/antenna panel group comprisesat least one of: a beam/antenna panel group identification for theparticular beam/antenna panel group, a maximum reference signal receivedpower (RSRP) value of the particular beam/antenna panel group, arelative power resolution window for the particular beam/antenna panelgroup in decibel (dB), a pre-configured relative power resolution windowin dB, a relative n-bit relative power offset value definingdifferential power offset with respect to the maximum RSRP value of theparticular beam/antenna panel group, and N-different transmitter beamindices for the particular beam/antenna panel group.
 9. The apparatus ofclaim 7, wherein the full reporting mode configuration common for theplurality of beam/antenna panel groups includes at least one of: acommon report for the plurality of beam/antenna panel groups, andgroup-specific reporting.
 10. The apparatus of claim 9, wherein thecommon report for the plurality of beam/antenna panel groups comprisesat least one of: a maximum reference signal received power valueassociated with the plurality of beam/antenna panel groups, one of arelative power resolution window common for the plurality ofbeam/antenna panel groups, and a pre-configured relative powerresolution window in dB.
 11. The apparatus of claim 9, wherein thegroup-specific reporting comprises at least one of: a beam/antenna panelgroup identification, a relative n-bit relative power offset valuedefining differential power offset to a maximum reference signalreceived power value over the plurality of beam/antenna panel groups,and N-different transmitter beam indices for a beam/antenna panel group.12. The apparatus of claim 7, wherein the differential reporting modeincludes at least one of a single-level non-group-wise differential beamreport and a multi-level non-group-wise differential beam report for Nscheduled Channel State Information Reference Signal (CSI-RS) antennaports (APs) or N-previously reported transmitted beams.
 13. Theapparatus of claim 12, wherein the single-level non-group-wisedifferential beam report comprises at least one of: a maximum referencesignal received power value over the plurality of beam/antenna panelgroups; and N different 1-bit relative power offset value for eachbeam/antenna panel group.
 14. The apparatus of claim 12, wherein themulti-level non-group-wise differential beam report for N scheduledCSI-RS APs or N-previously reported transmitted beams, for all beamgroups, comprises at least one of: a maximum reference signal receivedpower value over the plurality of beam/antenna panel groups; and arelative power resolution value, only if a computed power resolutionvalue differs X dB from a previously reported relative power resolutionvalue.
 15. The apparatus of claim 14, wherein the multi-levelnon-group-wise differential beam report for N scheduled CSI-RS APs orN-previously reported transmitter beams, for the plurality ofbeam/antenna panel groups, comprises, for N transmitter beams, n-bitrelative power offset from the maximum RSRP value over the plurality ofbeam/antenna panel groups.
 16. The apparatus of claim 7, wherein thepartial reporting mode includes at least one of multi-level partial beamreport for N-previously reported transmitter beam indices with trackingtransmitter beam tracking capability of L<N new transmitter beams, andmulti-level partial beam report for N-previously reported transmitterbeam indices with transmitter beam tracking capability of L<N newstrongest transmitter beams.
 17. The apparatus of claim 16, wherein themulti-level partial beam report for N-previously reported transmitterbeam indices with transmitter beam tracking capability of L<N newtransmitter beams comprises at least one of: a maximum RSRP value overthe plurality of beam/antenna panel groups, relative power resolutionvalue is only reported if the computed power resolution value differs XdB from previously reported relative power resolution value.
 18. Theapparatus of claim 16, wherein transmitter beam index comprises at leastone of a configured reference signal (RS) resource, a RS resource index,and a RS antenna port, wherein RS comprises at least one of ChannelState Information Reference Signal (CSI-RS), Demodulation ReferenceSignal (DMRS) of New Radio Physical downlink Control Channel (NR-PDCCH),NR_Physical Downlink Shared Channel (PDSCH) and a RS enabling beammanagement functionality.
 19. The apparatus of claim 16, wherein theapparatus is further caused to: apply source coding to further compresssignalled bits using at least one of run-length and Lempel-Ziv.
 20. Anapparatus, comprising: at least one processor; and at least onenon-transitory memory including computer program code, the at least onememory and the computer program code configured to, with the at leastone processor, cause the apparatus to at least: configure at least onereporting mode for transmitter beam index reporting for a particularbeam/antenna panel group from a plurality of beam/antenna groups,wherein the at least one reporting mode comprises at least one of a fullreporting mode configuration for the particular beam/antenna panelgroup, a full reporting mode configuration common for the plurality ofbeam/antenna panel groups, a differential reporting mode, and a partialreporting mode; and send the configured at least one reporting mode to auser equipment.